/*      $OpenBSD: print-sl.c,v 1.22 2021/12/01 18:28:46 deraadt Exp $   */

/*
 * Copyright (c) 1989, 1990, 1991, 1993, 1994, 1995, 1996, 1997
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code distributions
 * retain the above copyright notice and this paragraph in its entirety, (2)
 * distributions including binary code include the above copyright notice and
 * this paragraph in its entirety in the documentation or other materials
 * provided with the distribution, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University nor the names of its contributors may be used to endorse
 * or promote products derived from this software without specific prior
 * written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <sys/time.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>

#include <net/if.h>

#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>
#include <netinet/udp.h>
#include <netinet/tcp.h>

#include <net/slcompress.h>

#include <ctype.h>
#include <netdb.h>
#include <pcap.h>
#include <stdio.h>
#include <limits.h>

#include "interface.h"
#include "addrtoname.h"
#include "extract.h"                    /* must come after interface.h */

static u_int lastlen[2][256];
static u_int lastconn = 255;

static void sliplink_print(const u_char *, const struct ip *, u_int);
static void compressed_sl_print(const u_char *, const struct ip *, u_int, int);

/*
 * Definitions of the pseudo-link-level header attached to slip
 * packets grabbed by the packet filter (bpf) traffic monitor.
 */
#define SLIP_HDRLEN     16              /* BPF SLIP header length */

/* Offsets into BPF SLIP header. */
#define SLX_DIR         0               /* direction; see below */
#define SLX_CHDR        1               /* compressed header data */
#define CHDR_LEN        15              /* length of compressed header data */

#define SLIPDIR_IN      0               /* incoming */
#define SLIPDIR_OUT     1               /* outgoing */

/* XXX needs more hacking to work right */

void
sl_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
{
        u_int caplen = h->caplen;
        u_int length = h->len;
        const struct ip *ip;

        ts_print(&h->ts);

        if (caplen < SLIP_HDRLEN || length < SLIP_HDRLEN) {
                printf("[|slip]");
                goto out;
        }
        /*
         * Some printers want to get back at the link level addresses,
         * and/or check that they're not walking off the end of the packet.
         * Rather than pass them all the way down, we set these globals.
         */
        packetp = p;
        snapend = p + caplen;

        length -= SLIP_HDRLEN;

        ip = (struct ip *)(p + SLIP_HDRLEN);

        if (eflag)
                sliplink_print(p, ip, length);

        switch (ip->ip_v) {
        case 4:
                ip_print((u_char *)ip, length);
                break;
        case 6:
                ip6_print((u_char *)ip, length);
                break;
        default:
                printf ("ip v%d", ip->ip_v);
        }

        if (xflag)
                default_print((u_char *)ip, caplen - SLIP_HDRLEN);
 out:
        putchar('\n');
}


void
sl_bsdos_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
{
        u_int caplen = h->caplen;
        u_int length = h->len;
        const struct ip *ip;

        ts_print(&h->ts);

        if (caplen < SLIP_HDRLEN) {
                printf("[|slip]");
                goto out;
        }
        /*
         * Some printers want to get back at the link level addresses,
         * and/or check that they're not walking off the end of the packet.
         * Rather than pass them all the way down, we set these globals.
         */
        packetp = p;
        snapend = p + caplen;

        length -= SLIP_HDRLEN;

        ip = (struct ip *)(p + SLIP_HDRLEN);

#ifdef notdef
        if (eflag)
                sliplink_print(p, ip, length);
#endif

        ip_print((u_char *)ip, length);

        if (xflag)
                default_print((u_char *)ip, caplen - SLIP_HDRLEN);
 out:
        putchar('\n');
}

static void
sliplink_print(const u_char *p, const struct ip *ip, u_int length)
{
        int dir;
        u_int hlen;

        dir = p[SLX_DIR];
        putchar(dir == SLIPDIR_IN ? 'I' : 'O');
        putchar(' ');

        if (nflag) {
                /* XXX just dump the header */
                int i;

                for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i)
                        printf("%02x.", p[i]);
                printf("%02x: ", p[SLX_CHDR + CHDR_LEN - 1]);
                return;
        }
        switch (p[SLX_CHDR] & 0xf0) {

        case TYPE_IP:
                printf("ip %d: ", length + SLIP_HDRLEN);
                break;

        case TYPE_UNCOMPRESSED_TCP:
                /*
                 * The connection id is stored in the IP protocol field.
                 * Get it from the link layer since sl_uncompress_tcp()
                 * has restored the IP header copy to IPPROTO_TCP.
                 */
                lastconn = ((struct ip *)&p[SLX_CHDR])->ip_p;
                hlen = ip->ip_hl;
                hlen += ((struct tcphdr *)&((int *)ip)[hlen])->th_off;
                lastlen[dir][lastconn] = length - (hlen << 2);
                printf("utcp %d: ", lastconn);
                break;

        default:
                if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) {
                        compressed_sl_print(&p[SLX_CHDR], ip,
                            length, dir);
                        printf(": ");
                } else
                        printf("slip-%d!: ", p[SLX_CHDR]);
        }
}

static const u_char *
print_sl_change(const char *str, const u_char *cp)
{
        u_int i;

        if ((i = *cp++) == 0) {
                i = EXTRACT_16BITS(cp);
                cp += 2;
        }
        printf(" %s%d", str, i);
        return (cp);
}

static const u_char *
print_sl_winchange(const u_char *cp)
{
        short i;

        if ((i = *cp++) == 0) {
                i = EXTRACT_16BITS(cp);
                cp += 2;
        }
        if (i >= 0)
                printf(" W+%d", i);
        else
                printf(" W%d", i);
        return (cp);
}

static void
compressed_sl_print(const u_char *chdr, const struct ip *ip,
                    u_int length, int dir)
{
        const u_char *cp = chdr;
        u_int flags, hlen;

        flags = *cp++;
        if (flags & NEW_C) {
                lastconn = *cp++;
                printf("ctcp %d", lastconn);
        } else
                printf("ctcp *");

        /* skip tcp checksum */
        cp += 2;

        switch (flags & SPECIALS_MASK) {
        case SPECIAL_I:
                printf(" *SA+%d", lastlen[dir][lastconn]);
                break;

        case SPECIAL_D:
                printf(" *S+%d", lastlen[dir][lastconn]);
                break;

        default:
                if (flags & NEW_U)
                        cp = print_sl_change("U=", cp);
                if (flags & NEW_W)
                        cp = print_sl_winchange(cp);
                if (flags & NEW_A)
                        cp = print_sl_change("A+", cp);
                if (flags & NEW_S)
                        cp = print_sl_change("S+", cp);
                break;
        }
        if (flags & NEW_I)
                cp = print_sl_change("I+", cp);

        /*
         * 'hlen' is the length of the uncompressed TCP/IP header (in words).
         * 'cp - chdr' is the length of the compressed header.
         * 'length - hlen' is the amount of data in the packet.
         */
        hlen = ip->ip_hl;
        hlen += ((struct tcphdr *)&((int32_t *)ip)[hlen])->th_off;
        lastlen[dir][lastconn] = length - (hlen << 2);
        printf(" %d (%d)", lastlen[dir][lastconn], (int)(cp - chdr));
}